Draining fluid from storage containers



Nov. 2, 1965 B. BENGTSSON 3,214,927

DRAINING FLUID FROM STORAGE CONTAINERS Filed June 10, 1963 IN uemog Arming/s United States Patent 3,214,927 DRAINING FLUID FROM STORAGE C0llTAiNERS Bo Bengtsson, Paris, France, assignor to Oivind Lorentzen, Oslo, Norway Filed June 10, 1963, Ser. No. 286,793 2 Claims. (Cl. 62-45) The present invention relates to means for draining or delivery of fluid from containers which are equipped with means so as to be capable of containing fluid at a temperature considerably below ambient temperature, or other dangerous fluids, in particular liquified gas or other liquids at a pressure near to ambient pressure and at a temperature at or slightly underneath the boiling point of the fluid in question. In draining or delivery means for this purpose, it is of importance that the suction pipe of the pump is as short as possible and that the pump is provided with a certain static fluid pressure. Of safety reasons, certain rules are given regarding the positioning of the draining equipment and of the tubing to and from the same. Of such reasons, it has been suggested to arrange the draining equipment permanently and freely in the interior of the fluid container, the pump being driven by means of a directly connected electric motor or through a shaft which is carried through the container wall. It has also been suggested to arrange the draining equipment in an insulated column which is extending along the entire height of the container, from the outside of the top wall down to underneath the inside of the bottom wall of the same.

Such known arrangements are burdened with certain serious disadvantages, in particular with maintenance supervision and replacement of the draining equipment and the drive motor of the same. In particular, the electric leads to the drive motor, have caused difficulties, both with regard to their own insulation and their installation.

The present invention provides a drainage arrangement, wherein the inconveniences referred to are avoided, as the arrangement permits the use of conventional drainage pumps and electric motors without any risk of leakage from the fluid container and without claiming much space.

According to the invention, this is achieved by placing the drainage equipment in a pressure resistant chamber which is arranged to be kept filled with fluid which is preferably not combustible, and of a freezing point underneath the operational temperature of the fluid envisaged to be stored in the container. Thus, the drainage equipment chamber forms an independent, closed unit which is only connected with the fluid container proper through the suction line of the drainage pump, while the pressure line may be arranged in any suitable manner. Hereby, it is possible to arrange the drainage equipment chamher in just that manner which is deemed most suitable under the local conditions prevailing, i.e., inside the fluid container, on the outside surface of the container or freely in the space surrounding the container.

Due to the fact that the drainage equipment chamber is independent of the fluid container, it is also possible to so form the chamber that it may be used also for the drainage of the space surrounding the fluid container, in case a leakage should occur from the latter. Hereby, the separate drainage equipment for this purpose usually provided, is avoided.

In order to keep the drainage equipment chamber permanently filled with its own fluid under a certain pressure, it is convenient to make the chamber communicate with its surroundings through a rising pipe provided with an expansion vessel. This rising tube may then conveniently be utilised as passage for the electric leads to the drive motor of the drainage equipment, when the motor is ice mounted in the chamber, whereby such leads may be kept isolated from the atmosphere, possibly the fluid, which might be contained in the space surrounding the chamber.

The accompanying drawing illustrates, schematically and highly simplified, an example of how the arrangement of the invention may be brought into practice. The drawing is a vertical sectional view through a container intended to contain a liquid, such as condensed gas.

In the drawing, 1 is the fluid container proper, sur rounded by a suitable heat insulation 2. The space 3 between the Wall of the container 1 and the insulation 2 is shown highly exaggerated in the drawing, as this space in practice may be completely or partially included in the insulation. Mounted on the wall of the container 1 is a chamber 4 which contains a drainage pump 5 with associated drive motor 6. The chamber 4 is made fluid tight and pressure resistant and is provided with a rising tube 7 provided with an expansion vessel 8, for the purpose of maintaining the chamber filled, under a certain pressure, with a, preferably non-combustible fluid of such a type as is maintained liquid at the operational temperature of the particular fluid which is to be stored in the container 1.

Between suitable fluids adapted for the filling of the chamber 4, reference may be made to brine, glycol or gaseous carbon dioxide or nitrogen. The rising tube 7 is utilized as a passage for the electric leads 9 to the motor 6, so that a particular passage through the chamber wall is avoided, and the leads are kept isolated from the atmosphere, possibly the liquid, which might be present in the space 3 around the chamber 4 and the container 1.

The pump 5 is communicating with the interior of the container 1 through a suction line provided with shut off cock 10, while the pressure line 11, with its cock 16 leading to a main drainage line 12, is carried through the container 1. The pump 5 is also communicating with the space 3 through shut off cocks 13 and 14 through the interior of the chamber 4. Thus, by suitable operation of the various cocks 10, 13 and 14, it is possible to utilize one and the same pump 5 for the draining of the container 1, and for the draining of the space 3 through the chamber 4, at the same time as it is achieved that a possible leakage through the cocks 1i and/or 16 must pass both cocks 13 and 14 before entering the space 3.

For supervision and possible replacement of the drainage equipment with associated motor, an access port 15, provided with a shutter is arranged in the wall of the chamber 4.

In the case wherein the chamber 4 is mounted in the container 1, the arrangement is similar to that shown in the drawing, with the rising tube 7 extending upwardly through the top of the container 1 and with the expansion vessel 8 positioned outside of the latter.

If so desired, the motor 6 may obviously be placed outside of the insulation 2, the shaft being then carried in sealed condition through the insulation. In this manner the arrangement of the electric leads is simplified, but in return, the shaft must be provided with leading-in bushings due to the difference between the temperatures reigning on either side of the insulation 2 and also due to the sealing against fluid leakage.

I claim:

1. An insulated container, including draining means, adapted for storage of a liquid at substantially ambient pressure, said liquid having a boiling point substantially below ambient temperature, said insulated container comprising a storage chamber for containing said liquid and a pressure resistant chamber containing a pump and under normal operating conditions a second liquid under pressure, said second liquid being non-combustible and having a freezing point below the boiling point of said liquid in said storage chamber, a first conduit connecting said storage chamber with the inlet of said pump, a second conduit connecting said pressure resistant chamber with the inlet of said pump, and a third conduit connecting said pressure resistant chamber with said insulatedstorage container, each of said conduits having a valve therein for controlling the flow of liquid, and a drain pipe connected to the outlet of said pump for conveying liquid out of said insulated container such that by regulating said valves said pump may serve to drain said storage chamber, said pressure resistant chamber, and said insulated container.

2. An insulated container as claimed in claim 1 further comprising an expansion chamber located above and communicating with said pressure resistant chamber and being at least partially filled with said second liquid under normal operating conditions.

References Cited by the Examiner UNITED STATES PATENTS ROBERT A. OLEARY, Primary Examiner. 

1. AN INSULATED CONTAINER, INCLUDING DRAINING MEANS, ADAPTED FOR STORAGE OF A LIQUID AT SUBSTANTIALLY AMBIENT PRESSURE, SAID LIQUID HAVING A BOILING POINT SUBSTANTIALLY BELOW AMBIENT TEMPERATURE, SAID INSULATED CONTAINER COMPRISING A STORAGE CHAMBER FOR CONTAINING SAID LIQUID AND A PRESSURE RESISTANT CHAMBER CONTAINING A PUMP AND UNDER NORMAL OPERATING CONDITIONS A SECOND LIQUID UNDER PRESSURE, SAID SECOND LIQUID BEING NON-COMBUSTIBLE AND HAVING A FREEZING POINT BELOW THE BOILING POINT OF SAID LIQUID IN SAID STORAGE CHAMBER, A FIRST CONDUIT CONNECTING SAID STORAGE CHAMBER WITH THE INLET OF SAID PUMP, A SECOND CONDUIT CONNECTING SAID PRESSURE RESISTANT CHAMBER WITH THE INLET OF SAID PUMP, AND A THIRD CONDUIT CONNECTING SAID PRESSURE RESISTANT CHAMBER WITH SAID INSULATED STORAGE CONTAINER, EACH OF SAID CONDUITS HAVING A VALVE THEREIN FOR CONTROLLING THE FLOW OF LIQUID, AND A DRAIN PIPE CONNECTED TO THE OUTLET OF SAID PUMP FOR CONVEYING LIQUID OUT OF SAID INSULATED CONTAINER SUCH THAT BY REGULATING SAID VALVES SAID PUMP MAY SERVE TO DRAIN SAID STORAGE CHAMBER, SAID PRESSURE RESISTANT CHAMBER, AND SAID INSULATED CONTAINER. 